Several scientists contributed to the knowledge of the atom. Move each contribution to the correct...

Several scientists contributed to the knowledge of the atom. Move each contribution to the correct scientist.
J.J. Thomson
James Chadwick
Frederick Soddy
Drag each item to the correct category above.
The same element can have different atomic masses.
Atoms contain smaller, negatively-charged electrons that are easily removed.
Variable numbers of neutrons can cause the atoms of a single element to have different masses.